Constantly getting signed out & kicked from text chats.

For the past 3 years I've had a problem with my PS3. Every 10 minutes to every hour I will get kicked from PSN text chats. I've tried almost everything, but can't seem to find a solution to this problem. I thought it might have been a problem with my ISP, so I switched ISP's. After switching ISP's the problem still exists and has gotten worse. Any suggestions?